JP2006289963A - Liquid discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharge head which permits the realization of high-density driving elements and wiring to the driving elements in accordance with densely arranged discharge holes and pressure chambers and realization of stable discharge. <P>SOLUTION: In the liquid discharge head, piezoelectric elements 26 two-dimensionally arranged correspondingly to two-dimensionally arranged nozzles 12 and the pressure chambers 14 are joined the pressure chambers 14 of a piezoelectric element arrangement surface 24A and to an SWIC 23 mounted on an electrical wiring structure 45 to be joined to the opposite side through a vertical conducting member 38 vertically formed from a pad 22 and a horizontal conducting member 46. Consequently, electrical wiring to transmit a driving signal can be densely formed. The electrical wiring structure 45 has a structure in which an insulating structural member 40, an insulating member 42, and a heat dissipating member 44 to be joined to the piezoelectric element arrangement surface 24A are sequentially stacked from below from the piezoelectric element arrangement surface 24A and the SWIC 23 is mounted on the heat dissipating member 44. Thus a temperature variation of inks in the head 100 due to the heating of the SWIC 23 can be restrained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, and more particularly, to a technology for increasing the density of a drive element wiring, a drive circuit, and the like that apply a discharge force to a liquid discharged from a discharge hole.

  In recent years, ink jet recording apparatuses have become widespread as data output apparatuses for images and documents. The ink jet recording apparatus drives an actuator corresponding to a nozzle provided in a print head according to data, and ejects ink from the nozzle to form an image, a document, or the like according to the data on a medium.

  In the ink jet recording apparatus, there is an increasing demand for higher quality of the result image. A high quality of the resulting image is achieved by constructing the image with minute size dots arranged at high density. In order to reduce the dot size, the nozzle diameter can be reduced to reduce the amount of ink droplets ejected from the nozzle at one time. To increase the dot arrangement, the nozzle density is increased and the dots are increased. Droplet ejection control may be performed according to the high density of the arrangement.

  Further, in a configuration in which ink ejection force is obtained by an actuator such as a piezoelectric element, when the nozzle arrangement is increased in density, the actuators are also arranged at a higher density in accordance with the nozzle arrangement. When the actuators are arranged at a high density, it becomes difficult to arrange the wiring for transmitting the drive signal to the actuator on the actuator arrangement surface, and the wiring is formed by using a wiring member such as a multilayered flexible substrate. Once pulled out from the arrangement surface in the vertical direction, it is arranged in the horizontal direction, and high-density arrangement of the actuator and the wiring to the actuator is realized.

  In the actuator device, the ink jet recording head, and the ink jet recording device described in Patent Document 1, a mounting portion to which external wiring is connected is provided in a region opposite to the piezoelectric element, and one end thereof is connected to the mounting portion. And having a connecting member provided with a driving wiring connected to the piezoelectric element at the other end, and connecting the connecting member to the piezoelectric element side of the flow path forming substrate on which the nozzle and the pressure chamber are formed, Simplification and downsizing of the structure of the ink jet recording head are realized.

  Further, in the ink jet head, ink jet recording apparatus, and multilayer piezoelectric element described in Patent Document 2, the external electrode drawn on the step portion of the piezoelectric element having an L-shaped cross section is bonded to the through hole of the multilayer ceramic substrate by wire bonding. Wired and mounted on the opposite side of the multilayer ceramic substrate with a driver IC that is electrically connected to the external electrode. The piezoelectric element wiring workability and reliability are high, and the structure is simple and compact. The head is realized.

In the recording head described in Patent Document 3, a single-crystal silicon substrate without a joint portion on which a nozzle, a pressure chamber, a vibration plate, a common ink chamber, and the like are formed, and a head housing portion are included. Since the ink jet recording head is configured, a simple structure with few components is realized.
JP 2003-136721 A Japanese Patent Laid-Open No. 2003-251813 Japanese Patent Laid-Open No. 9-327912

  However, there is a limit to increasing the wiring density depending on the current capacity and size of a wiring member such as a flexible substrate used when the wiring is pulled out from the actuator in the horizontal direction. For example, when a flexible substrate is used for the wiring member, it is possible to increase the wiring density by multilayering the flexible substrate, but there is a limit to multilayering of the flexible substrate in terms of manufacturing difficulty and strength. .

  In addition, in order to reduce the size of the head, a drive circuit that drives the actuator may be mounted on the above-described flexible substrate or the structural member of the head, and the temperature variation of the ink increases due to the heat generated from the drive circuit. There is. When the temperature fluctuation of the ink becomes large, the ejection becomes unstable and the ejection performance is greatly reduced.

  In the actuator device, the ink jet recording head, and the ink jet recording device described in Patent Document 1, high-precision positioning is required when joining the joining member and the flow path forming substrate, and the manufacturing difficulty increases. End up. Also, depending on the heat dissipation design of the mounting part provided on the joining member, the heat generated from the drive circuit (driver IC) mounted on the mounting part is conducted to the flow path forming substrate, changing the temperature of the ink in the pressure generating chamber. There is a risk of letting you.

  Further, in the ink jet head, the ink jet recording apparatus, and the multilayer piezoelectric element described in Patent Document 2, since the piezoelectric element having an L-shaped cross section is formed, the manufacturing process of the piezoelectric element becomes complicated, and the difficulty in manufacturing the piezoelectric element. Becomes higher. In addition, since there is a step portion from which the external electrode of the piezoelectric element is drawn, this hinders high-density arrangement of the piezoelectric elements.

  Further, the recording head described in Patent Document 3 discloses only a technique that realizes a simple structure with few components and does not disclose high-density arrangement in the recording head.

  The present invention has been made in view of such circumstances, and realizes high density of the drive element and wiring to the drive element according to the discharge holes and pressure chambers arranged at high density, and stable discharge. An object of the present invention is to provide a liquid discharge head that realizes the above.

  In order to achieve the above object, a liquid discharge head according to the present invention is provided corresponding to a plurality of discharge holes arranged in a two-dimensional shape for discharging liquid onto a discharge target medium, and the plurality of discharge holes. A plurality of pressure chambers for storing liquid to be discharged from the discharge holes, a common liquid chamber for supplying liquid to the plurality of pressure chambers, and a wall in which the discharge holes are formed among the walls constituting the pressure chamber A piezoelectric element having an individual electrode to which a drive signal is input, a take-out electrode taken out from the individual electrode and electrically connected to the individual electrode, and the pressure A structural member joined to a surface of the wall constituting the chamber opposite to the liquid discharge direction, and a drive circuit mounted on a surface of the structural member that comes into contact with the atmosphere to generate a drive signal applied to the piezoelectric element. The structural member comprises It has a laminated structure in which the above members are laminated, at least the outermost layer in contact with the atmosphere is composed of a heat radiating member, and has at least one heat insulating member, and the member that forms the structural member is the piezoelectric member It includes at least the vertical conductive member among a vertical conductive member formed in a direction substantially perpendicular to a surface to which the element is attached and a horizontal conductive member formed in a direction substantially orthogonal to the vertical conductive member, and one end of the vertical conductive member It has a conductive member joined to the electrode and the other end joined to the drive circuit.

According to the present invention, in a liquid discharge head having discharge holes and pressure chambers arranged two-dimensionally, a wiring member that transmits a drive signal to a piezoelectric element provided corresponding to each pressure chamber is provided with a heat insulating member and a heat dissipation member. A vertical conductive member formed so as to penetrate a structural member (upper structure) including a member and a horizontal conductive member formed in a direction substantially orthogonal to the vertical conductive member are configured to include at least the vertical conductive member. . Therefore, it is possible to easily realize a high density of electrical wiring between the piezoelectric element driving circuit and the piezoelectric element.

  Further, the structural member is composed of a heat radiating member provided in the outermost layer and one or more heat insulating members, and is configured to mount a driving circuit for driving the piezoelectric element on the heat radiating member. The heat generated from the drive circuit can be efficiently released to the outside, and the influence of the heat generated from the drive circuit on the inside of the liquid discharge head (liquid discharged from the liquid discharge head) can be reduced.

  The conductive member may be constituted by one vertical conductive member (a piezoelectric element and a drive circuit may be joined via one vertical conductive member), or may be constituted by a vertical conductive member and a horizontal conductive member. May be. The conductive member may include a plurality of vertical conductive members and a plurality of horizontal conductive members.

  The vertical conductive member may be formed so as to penetrate the entire structural member, or may be formed so as to penetrate at least one member of the heat insulating member and the heat radiating member, and another vertical member via the horizontal conductive member. It may be joined to a conductive member or a drive circuit. Note that if the conductive member is covered with insulation (insulation treatment), a metal can be used as the heat dissipation member.

  The piezoelectric element that applies discharge force to the liquid discharged from the discharge hole may include a common piezoelectric body (piezoelectric member) in a plurality of pressure chambers, and the piezoelectric body may include individual electrodes corresponding to the pressure chambers. However, a piezoelectric body and individual electrodes may be provided for each pressure chamber (mechanical division). The piezoelectric element may have a laminated structure in which a plurality of piezoelectric bodies and electrodes are alternately laminated.

  The liquid discharge head includes a line-type head having a discharge hole array having a length corresponding to the dischargeable width of a medium to be discharged that receives the liquid discharged from the discharge holes, and a discharge length less than the dischargeable width. There is a shuttle type head that has a hole array and discharges liquid over the entire width in the width direction of the discharge medium while relatively moving the discharge medium and the liquid discharge head in the width direction of the discharge medium.

  Note that the medium to be ejected is a medium (medium) that receives the liquid ejected by the liquid ejection head, and includes resin sheets such as continuous paper, cut paper, seal paper, and OHP sheet, film, cloth, and other materials and shapes. Regardless, it includes various media.

  A second aspect of the invention relates to an aspect of the liquid discharge head according to the first aspect, wherein the structural member is bonded to a surface of the wall constituting the pressure chamber opposite to the liquid discharge direction. It has the characteristic structure member.

  By providing an insulating structural member that supports the heat insulating member and the heat radiating member on the surface joined to the pressure chamber of the structural member, it is possible to reliably support the heat insulating member, the heat radiating member, and the drive circuit mounted on the heat radiating member. The rigidity of a predetermined head can be ensured. Moreover, the insulation process given to a heat insulating member or a heat radiating member becomes unnecessary.

  A third aspect of the present invention relates to an aspect of the liquid discharge head according to the first or second aspect, wherein the drive circuit has a structure integrated in one or more ICs, and the ICs are the heat radiating members. It is characterized by being flip-chip mounted on the surface on which the driving circuit is mounted.

The drive circuit that generates the drive signal for the piezoelectric element is integrated in one or more ICs, and this IC is flip-chip mounted on the drive circuit mounting surface of the heat dissipation member, so that the drive circuits can be mounted with high density. The area (area) occupied by the drive circuit in the surface on which the drive circuit is mounted can be reduced. Further, since the drive circuits can be dispersedly arranged, it is possible to reduce the arrangement density of the vertical conductive members and the horizontal conductive members in the vicinity of each drive circuit.

  The drive circuit mounting surface may be on the side opposite to the heat insulating member of the heat radiating member (upper surface side of the heat radiating member) or on the heat insulating member side (lower surface side of the heat radiating member).

  The invention according to claim 4 relates to an aspect of the liquid discharge head according to claim 1, 2, or 3, wherein the relationship between the thermal conductivity α1 of the heat radiating member and the thermal conductivity β of the heat insulating member is: The following expression α1> β is satisfied.

  In terms of heat dissipation of the drive circuit, the heat dissipation member is preferably a member having a thermal conductivity α1 exceeding 15 (W / m · K), and members satisfying this condition include ceramics such as alumina and metal members. Further, in terms of temperature control in the common liquid chamber, the heat insulating member is preferably a member having a thermal conductivity β of less than 1 (W / m · K), and members satisfying this condition include epoxy resin and glass.

  A fifth aspect of the present invention relates to an aspect of the liquid discharge head according to any one of the first to fourth aspects, wherein the insulating structural member contains inorganic fine particles in a thermosetting epoxy resin. It is characterized by including a member.

  A material in which inorganic fine particles are contained in a thermosetting epoxy resin or a thermosetting epoxy resin has high heat resistance and is suitable for flip-chip bonding of a drive circuit. In addition, since it has high electrical insulation and low water absorption, it is suitable for use in a structure constituting a liquid discharge head.

  A sixth aspect of the present invention relates to an aspect of the liquid ejection head according to any one of the first to fifth aspects, wherein the drive circuit includes a heat radiating member for the drive circuit.

  By providing the drive circuit with a heat radiating member for the drive circuit, the heat generated from the drive circuit can be effectively released to the outside.

  A metal member having high thermal conductivity such as copper or aluminum may be used for the heat radiating member for the drive circuit.

  A seventh aspect of the invention relates to an aspect of the liquid discharge head according to the sixth aspect of the invention, and the relationship between the thermal conductivity α2 of the heat radiating member for the drive circuit and the thermal conductivity β of the heat insulating member is expressed by the following equation: It is characterized by satisfying α2> β.

  The thermal conductivity α2 of the heat radiating member for the drive circuit may be approximately the same as the thermal conductivity α1 of the heat radiating member on which the drive circuit is mounted. Further, the heat conductivity α2 of the heat radiating member for the drive circuit may be larger or smaller than the heat conductivity α1 of the heat radiating member.

  An eighth aspect of the present invention relates to an aspect of the liquid discharge head according to any one of the first to seventh aspects, wherein the common liquid chamber and the piezoelectric element are arranged in a liquid discharge direction of the pressure chamber. Provided on the opposite side, the conductive member is provided so as to rise from the surface on which the piezoelectric element is disposed and penetrate the common liquid chamber, one end is joined to the extraction electrode, and the other end is the drive It is characterized by being joined to a circuit.

When the common liquid chamber is provided on the liquid discharge direction side of the pressure chamber, the size of the common liquid chamber is reduced when the discharge holes and pressure chambers are densified, and the liquid is discharged to the pressure chamber when discharging liquid at a high discharge frequency. The liquid supply may not be in time. Further, if the common liquid chamber is enlarged, the length of the discharge side flow path from the pressure chamber to the discharge hole becomes long, and there is a possibility that a high discharge frequency cannot be maintained. Therefore, a flat common liquid chamber having a predetermined area is provided on the opposite side of the pressure chamber from the liquid discharge direction, and liquid is supplied from the common liquid chamber to a plurality of pressure chambers in the vertical direction, thereby providing a high discharge frequency. The liquid can be supplied without delay while maintaining the above.

  In addition, since it has a structure in which a conductive member that transmits a drive signal to the piezoelectric element is provided so as to rise from the arrangement surface of the piezoelectric element and penetrate the common liquid chamber, the piezoelectric element (individual electrode), pressure chamber, discharge It becomes possible to arrange | position a hole with high density.

  This conductive member is covered with an insulating structural member so as not to come into contact with the liquid stored in the common liquid chamber (so as to ensure a predetermined insulating performance).

  A ninth aspect of the present invention relates to an aspect of the liquid ejection head according to any one of the first to eighth aspects, wherein the drive circuit includes the pressure chamber in a region in contact with the heat radiating member. Or it is arrange | positioned in the area | region corresponding to the non-arrangement | positioning area | region of the said common liquid chamber.

  Since the drive circuit is arranged avoiding the area (liquid flow path range) where the common liquid chamber (liquid flow path) is disposed, the temperature fluctuation of the liquid in the liquid flow path due to heat generated from the drive circuit is reduced. Can be made. By reducing temperature fluctuations in the liquid flow path, it is possible to suppress an increase in liquid concentration and viscosity.

  A tenth aspect of the present invention relates to an aspect of the liquid discharge head according to any one of the first to ninth aspects, wherein the discharge medium has a length corresponding to the entire width of the liquid dischargeable width. It has a structure in which the discharge holes are arranged.

  In the line head corresponding to the entire width of the discharge medium, at least one of the liquid discharge head and the discharge medium is set once along the direction substantially perpendicular to the width direction of the discharge medium. By moving only the liquid, it is possible to discharge the liquid over the entire liquid dischargeable area of the discharge target medium. Liquid can be discharged over the entire area of the liquid dischargeable area of the discharged medium in a shorter time compared to a method in which a head having a width shorter than the width of the discharged medium is scanned in the width direction of the discharged medium.

  According to an eleventh aspect of the present invention, in the liquid ejection head according to the tenth aspect, the ejection hole array in which the ejection holes are arranged over a length that is less than a full width of the liquid ejectable width of the ejection target medium is provided. It has a structure in which a plurality of liquid discharge head modules are arranged in the width direction of the discharge target medium.

  Long heads corresponding to ejected media with large sizes (for example, poster size) change the ejection performance due to variations in manufacturing (assembly), and the difficulty in manufacturing becomes high. By combining a plurality of short heads that are easier to manufacture than the head, it is possible to easily manufacture a long head corresponding to a large-sized ejection target medium.

  The head modules may be arranged in a zigzag pattern and connected to form a length corresponding to the entire width of the medium to be ejected.

  According to the present invention, a conductive member that transmits a drive signal to a two-dimensionally arranged piezoelectric element, a structural member that is provided with a heat dissipating member on the outermost layer and one or more heat insulating members are provided. Since it is arranged so as to penetrate the extraction electrode in the vertical direction and is electrically connected to the drive circuit mounted on the surface of the structural member substantially perpendicular to the vertical wiring member, it is easy to increase the density of the electric wiring. Can be realized.

  In addition, since the driving circuit for driving the piezoelectric element is mounted on the heat radiating member, the heat generated from the driving circuit is efficiently released to the outside, and the heat insulating member is provided to generate the driving circuit. It is possible to reduce the influence of the heat to the inside of the liquid discharge head.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a perspective plan view showing the structure of a liquid discharge head (discharge device, hereinafter simply referred to as a head) 10 according to the first embodiment of the present invention, and FIG. FIG. 2 is a cross-sectional view showing the structure (a cross-sectional view taken along line 2-2 in FIG. 1).

  A head 10 shown in FIG. 1 is an ink jet head mounted on an ink jet recording apparatus that forms a desired image on a medium (a medium to be ejected) with ink ejected from ejection holes, for example. The head 10 may include what is called a print head or a recording head.

  As shown in FIG. 1, the head 10 contains a nozzle 12 (ejection hole) for ejecting ink (liquid), ink ejected from the nozzle 12, a pressure chamber 14 having a substantially square shape in plan view, and an ink supply. A supply throttle 18 for supplying ink from a system (not shown) to the pressure chamber 14 via a common liquid chamber (common flow path) 16, and a replenishing port 20 for supplying ink from the ink supply system to the common liquid chamber 16. The individual electrodes (not shown in FIG. 1, not shown in FIG. 1 and indicated by reference numeral 28 in FIG. 2) are provided in a piezoelectric element (not shown in FIG. 1, indicated by reference numeral 26 in FIG. 2) that gives ejection force to the ink accommodated in the pressure chamber 14. And a pad 22 (extraction electrode) extracted from the piezoelectric element to the outside.

  Although FIG. 1 shows a mode in which the pad 22 is provided outside the piezoelectric element 26, the pad 22 may be formed on the surface of the piezoelectric element 26 on which the individual electrode 28 is formed. Further, when a pad 22 is provided on a pressure plate (not shown in FIG. 1 and indicated by reference numeral 24 in FIG. 2) that is also used as a common electrode, an insulating layer (not shown) is provided between the pressure plate 24 and the pad. It is formed.

  In FIG. 1, a substantially square indicated by reference numeral 23 (illustrated by a broken line) is a switching IC (drive circuit, SWIC) that generates a drive signal for driving each piezoelectric element.

  The head 10 shown in FIG. 1 has six rows of nozzle groups in which two nozzles 12 are arranged in the row direction. The nozzle arrangement shown in FIG. 1 is merely an example, and one nozzle group may include two or more (or one) nozzles 12. Further, the number of nozzle groups in the row direction may be less than six rows, or may be six or more rows.

  Further, according to FIG. 2, the head 10 includes a piezoelectric element that applies ejection force to the ink stored in the pressure chamber 14 on the surface opposite to the pressure chamber 14 of the pressure plate 24 that forms the top surface of the pressure chamber 14. A (piezoelectric actuator) 26 is provided. The piezoelectric element 26 has an individual electrode 28 to which a drive signal is applied at the upper part (surface opposite to the pressure plate 24), and the common electrode provided on the surface opposite to the individual electrode 28 is a metal material such as SUS. It is also used as the pressure plate 24 made of (conductive material).

  When the pressure plate 24 is made of an insulating material (insulating material, non-conductive material) such as resin or ceramic, the surface opposite to the individual electrode 28 is made of a conductive member such as metal. A common electrode to be formed is provided.

FIG. 2 shows a mode in which the piezoelectric element 26 is provided on the opposite side of the pressure chamber 14 of the pressure plate 24 (that is, outside the pressure chamber 14). However, the piezoelectric element 26 is subjected to predetermined insulation treatment and ink resistance treatment. The piezoelectric element 26 may be provided on the pressure chamber 14 side of the pressure plate 24 (that is, inside the pressure chamber 14).

  In the aspect in which the piezoelectric element 26 is provided inside the pressure chamber 14, a wiring that penetrates the pressure plate 24 is provided so as to electrically connect the pad 22 provided outside the pressure chamber 14 and the individual electrode 28.

  As shown in FIG. 2, the head 10 has a laminated structure in which a plurality of cavity plates are laminated. That is, the head 10 includes a nozzle plate 30 in which the nozzles 12 are formed, a flow path such as the pressure chamber 14 and the common liquid chamber 16, and a flow path plate 32 in which a liquid chamber is formed. A pressure plate 24 is laminated.

  Further, a pad 22 drawn out from the individual electrode 28 to the outside of the piezoelectric element 26 is provided on the piezoelectric element mounting surface 24A of the pressure plate 24. The pad 22 is formed in a vertical direction substantially orthogonal to the pad 22. The vertical conductive member 38 is electrically joined.

  The vertical conductive member 38 is formed on the surface of the pressure plate 24 opposite to the pressure chamber 14 (piezoelectric element mounting surface 24A) and on the side opposite to the pressure plate 24 of the insulating structure member 40. The heat insulating member 42 is laminated, and the electric wiring structure 45 including the heat radiating member 44 laminated on the side opposite to the insulating structural member 40 of the heat insulating member 42 is formed so as to penetrate.

  The heat radiating member 44 is formed with a horizontal conductive member 46 whose one end is electrically joined to the vertical conductive member 38, and the other end of the horizontal conductive member 46 is opposite to the heat insulating member of the heat radiating member. It joins with switching IC23 mounted in the surface (drive circuit mounting surface) 44A.

  That is, as described above, the switching IC 23 and the individual electrode 28 of the piezoelectric element 26 are electrically joined via the drive signal transmission path including the horizontal conductive member 46, the vertical conductive member 38, and the pad 22. The generated drive signal is transmitted to the individual electrode 28 through the drive signal transmission path.

  An electronic component (electronic device) constituting the switching IC 23 shown in this example and an electrical wiring member (electrical wiring pattern) for electrically connecting them are formed in a bare chip (chip core) 50 through processes such as a semiconductor manufacturing process and a printing process. The input / output terminals of the bare chip 50 are directly joined to the protruding electrodes (bumps) 52 formed on the horizontal conductive member 46. That is, the switching IC 23 is flip-chip mounted on the heat dissipation member 44. In the method shown in FIG. 2, face-down mounting is performed in which the surface of the bare chip 50 faces the heat radiating member 44 side.

  A conductive adhesive is used for joining the protruding electrode 52 and the bare chip 50 described above. Further, a conductive adhesive is also used for joining the members constituting the drive signal transmission path. Of course, these members may be electrically joined by solder.

  When the flip chip mounting shown in this example is used, the mounting area of the switching IC 23 can be reduced as compared with the IC having the lead frame, and the high density arrangement and the distributed arrangement of the drive circuits are facilitated. In flip chip mounting, the wiring length is shorter than in wire bonding, and the inductor component due to the bonding wire can be removed. Therefore, electrical characteristics are improved (delay time in driving signal transmission is shortened), and high-speed operation is possible.

In order to protect the joint between the bare chip 50 and the protruding electrode 52, the bare chip 50 and its mounting region are sealed (molded) with an insulating member such as epoxy resin or silicon.

  FIG. 2 illustrates an aspect in which the horizontal conductive member 46 is formed on the side surface 44A opposite to the heat insulating member 44 of the heat radiating member 44. As illustrated in FIG. It may be formed on the heat radiating member side surface 42A or the insulating structural member side surface 42B of the heat insulating member 42, or on the heat insulating member side surface 40A or the piezoelectric element side surface 40B of the insulating structural member 40.

  That is, the horizontal conductive member 46 may be formed on any surface of the insulating structural member 40, the heat insulating member 42, and the heat radiating member 44 that intersects the vertical conductive member 38. Further, the horizontal conductive member 46 is formed on at least one of these surfaces.

  3 indicates the horizontal conductive member 46 formed on the heat radiating member side surface 42 </ b> A of the heat insulating member 42, and reference numeral 46 </ b> B indicates the horizontal conductive member 46 formed on the heat insulating member side surface 44 </ b> B of the heat radiating member 44. Reference numerals 46C and 46D denote horizontal conductive members 46 formed on the heat insulating member side surface 40A of the insulating structural member 40 and the insulating structural member side surface 42B of the heat insulating member 42, respectively.

  In other words, the electric wiring structure 45 having a structure in which the insulating structural member 40, the heat insulating member 42, and the heat radiating member 44 are sequentially laminated from the piezoelectric element disposition surface 24A side is joined to the piezoelectric element disposition surface 24A. A conductive member through which a drive signal to be applied to the piezoelectric element 26 is transmitted so as to penetrate the wiring structure 45 is formed. The conductive member includes a vertical conductive member 38 and a horizontal conductive member 46.

  As described above, the electrical wiring structure 45 has a multilayer structure, and the horizontal conductive members 46 are dispersed on the horizontal planes of the respective layers, whereby the arrangement density of the horizontal conductive members 46 formed on one horizontal plane can be reduced and 1 The vertical conductive members 38 formed in one layer can be dispersed, and the vertical conductive members 38 and the horizontal conductive members 46 can be easily patterned. Furthermore, it is more preferable to pattern the horizontal conductive member 46 formed on the horizontal plane of each layer in accordance with the position of the input / output terminal of the bare chip 50.

  Note that a protruding electrode 54 that is directly electrically connected to the vertical conductive member 38 is formed on the side surface 44A opposite to the heat insulating member 44 of the heat radiating member 44. The protruding electrode 54 is electrically connected to the input / output terminal of the bare chip 50. .

  Here, an insulating material such as an epoxy resin having a predetermined insulating performance and a predetermined strength may be used for the insulating structural member 40. In addition, the insulating structural member 40 is formed with a recess 40 </ b> C in a region where the piezoelectric element 26 is disposed so as not to prevent deformation of the pressure plate 24 and the piezoelectric element 26.

  A material such as epoxy resin or glass is used for the heat insulating member 42 so that heat generated from the switching IC 23 is not transmitted to the inside of the head 10 (particularly, the ink flow path such as the pressure chamber 14 and the common liquid chamber 16). Is provided. The thickness of the heat insulating member 42 is determined by the amount of ink replaced per unit time and the amount of heat generated by the switching IC 23 so that the ink temperature rise from room temperature falls within a predetermined range. The temperature rise range of the ink is preferably within a range from room temperature to 5 ° C.

  On the other hand, the heat radiating member 44 on which the switching IC 23 is mounted uses a material having high thermal conductivity such as ceramic such as alumina or a metal material, so that a predetermined heat radiating performance is secured, and heat generated from the switching IC 23 is transferred to the head 10. Efficient escape to the outside. When a metal material is used for the heat radiating member 44, a predetermined insulation process is applied to the region where the vertical conductive member 38 and the horizontal conductive member 46 are formed in order to ensure insulation from the vertical conductive member 38 and the horizontal conductive member 46. Is done.

  Thus, by multilayering the electrical wiring structure 45 in which the vertical conductive member 38 and the horizontal conductive member 46 are formed, and including a heat radiation layer (heat radiation member 44) and a heat insulation layer (heat insulation member 42) in this multilayer structure, The switching IC 23 can be mounted in the nozzle arrangement area (the area in which the nozzle on the nozzle plate 30 is arranged on the side surface 44A opposite to the heat insulating member 44), and the head 10 can be downsized. can do.

  Further, by mounting the switching IC 23 on the heat dissipation member 44 having a high thermal conductivity, the heat dissipation effect of the switching IC 23 can be obtained. On the other hand, at least one layer close to the ink flow path is formed by the heat insulating member 42 having a low thermal conductivity. By configuring, the temperature variation of the ink in the ink flow path due to the heat generation of the switching IC 23 can be reduced, and the ejection characteristics of the ejection device can be kept stable.

  Here, the relationship between the thermal conductivity α1 of the heat radiating member 44 and the thermal conductivity β of the heat insulating member 42 satisfies the following equation [Formula 1], and the thermal conductivity α1 of the heat radiating member 44 and the heat of the insulating structural member 40 The relationship with the conductivity γ satisfies the following equation [Equation 2].

[Equation 1]
α1> β
[Equation 2]
α1> γ
Note that the relationship between the thermal conductivity β of the heat insulating member 42 and the thermal conductivity γ of the insulating structural member 40 satisfies the following equation [Equation 3].

[Equation 3]
β ≦ γ
The thermal conductivity α1 in the case where ceramic is used for the heat radiating member 44 is as shown in the following equation [Equation 4].

[Equation 4]
15 (W / m · K) ≦ α1 ≦ 30 (W / m · K)
Further, the thermal conductivity α1 when alumina is used for the heat radiating member 44 is as shown in the following equation [Formula 5].

[Equation 5]
α1 = 17 (W / m · K)
Therefore, a material having a thermal conductivity of 15 (W / m · K) or more is preferably used for the heat dissipation member 44.

  On the other hand, the thermal conductivity β when an epoxy resin is used for the heat insulating member 42 is as shown in the following formula [Formula 6].

[Equation 6]
β = 0.19 (W / m · K)
Further, the thermal conductivity β when glass is used for the heat insulating member 42 is as shown in the following equation [Formula 7].

[Equation 7]
0.55 ≦ β ≦ 0.75 (W / m · K)
Therefore, a material having a thermal conductivity of 1 (W / m · K) or less is used for the heat insulating member 42 as a suitable material.

  The liquid discharge head 10 configured as described above is provided on the piezoelectric element disposition surface 24A from the individual electrode 28 of the piezoelectric element 26 disposed in the flow path structure constituting the flow path such as the pressure chamber 14 and the common liquid chamber 16. A vertical conductive member 38 is formed in the vertical direction (opposite to the ink discharge direction) on the drawn pad 22, and the vertical conductive member 38 is joined to the side opposite to the ink discharge direction of the flow path structure. A horizontal conductive member 46 which penetrates through the insulating structural member 40 and further passes through the heat insulating member 42 and the heat radiating member 44 stacked on the insulating structural member 40 and is mounted on the side surface 44A of the heat radiating member 44 opposite to the heat insulating member. It is comprised so that it may join with switching IC23. Therefore, electrical connection from the piezoelectric element 26 (individual electrode 28) provided corresponding to the pressure chambers 14 arranged at high density to the switching IC 23 can be facilitated.

  Further, the switching IC 23 is mounted on the heat radiating member 44 that releases the heat generated from the switching IC 23 to the outside of the head 10, and a heat insulating member 42 is provided between the switching IC 23 and the flow path structure member, and the heat generated from the switching IC 23. Since the heat is radiated to the outside without being transmitted to the head 10, the temperature variation of the ink in the head 10 can be reduced and preferable ink discharge can be realized.

  The heat insulation member 42 (heat insulation layer) may have a laminated structure in which a plurality of layers (members) are laminated, or the vertical wiring member 38 and the horizontal wiring member 46 are subjected to insulation coating (insulation treatment). Thus, a mode in which the heat insulating member 42 and the insulating structural member 40 are also used is possible.

[Second Embodiment]
Next, a liquid ejection head according to a second embodiment of the invention will be described. In addition, the same code | symbol is attached | subjected to the part which is the same or similar to 1st Embodiment in 2nd Embodiment, and the description is abbreviate | omitted.

  4 is a plan perspective view showing a structural example of the head 100 having the nozzles 12 arranged in a matrix. FIG. 5 is a cross-sectional view showing the three-dimensional structure of the head 100 (cross-sectional view taken along line 5-5 in FIG. 4). It is.

  In order to increase the density of dots formed on the medium by the ink ejected from the head 100 (to increase the dot pitch), it is necessary to increase the pitch of the nozzles 12 in the head 100. As shown in FIGS. 4 and 5, the head 100 of this example has a structure in which the nozzles 12 and the pressure chambers 14 corresponding to the nozzles 12 are arranged in a staggered matrix, thereby making the nozzle pitch apparent. High density is achieved.

  The pressure chamber 14 provided corresponding to each nozzle 12 has a substantially square planar shape, and the nozzle 12 and the supply restrictor 18 are provided at both corners on the diagonal line. Each pressure chamber 14 communicates with a common liquid chamber 16 via a supply throttle 18.

  A large number of nozzles 12 and pressure chambers 14 having such a structure are arranged in a grid pattern in a fixed arrangement pattern along a row direction along the main scanning direction and an oblique column direction having a constant angle θ not orthogonal to the main scanning direction. It has an arrayed structure. Due to the structure in which a plurality of nozzles 12 and pressure chambers 14 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction, the nozzle pitch P projected in the main scanning direction is d × cos θ.

  Although FIG. 4 shows the head 100 having the nozzles 12 arranged in a matrix of 4 rows and 6 columns, the head 100 may have more nozzles 12.

  That is, in the main scanning direction, each nozzle 12 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a high-density nozzle configuration in which the number of nozzle rows projected in the main scanning direction is 2400 per inch (2400 nozzles / inch).

  In the head 100 having the nozzles 12 arranged in such a matrix, as shown in FIG. 1, nozzles and pressure chambers in which the nozzles and pressure chambers projected on the heat insulating member opposite side surface 44 </ b> A of the heat radiating member 44 are arranged. When the switching IC 23 is disposed in the region 110 (illustrated by a two-dot broken line), the electrical connection pattern (horizontal conductive member 46) on the opposite side surface 44A of the heat insulating member becomes high density, and such a high density electrical connection pattern is formed. It is difficult to do.

  In order to solve the above problem, a nozzle arrangement in which the nozzle 12 is not arranged immediately below the area where the switching IC 23 is mounted (that is, the nozzle / pressure chamber area 110) is conceivable. Then, the pitch error of the nozzle 12 may be increased.

  Therefore, as shown in FIG. 6, the electrical wiring pattern can be easily formed by disposing the switching IC 23 in the peripheral area of the structure 120 of the head 100 (that is, the area excluding the nozzle / pressure chamber area 110). Can do.

  Further, as shown in FIG. 7 (a), when the switching IC 23 is not mounted in the ink flow path range 130 in which the region where the ink flow path is formed in the head 100 is projected on the opposite side surface 44A of the heat insulating member, the switching is performed. It is more preferable because the temperature generated in the ink flow path can be suppressed by the heat generated from the IC 23. In general, the area where the ink flow path range 130 shown in FIG. 7A is projected onto the drive circuit mounting surface is larger than the area where the nozzle / pressure chamber region 110 shown in FIGS. 4 and 6 is projected onto the drive circuit mounting surface. It is getting bigger.

  As shown in FIG. 7B, the drive circuit mounting surface on which the switching IC 23 is mounted may be a heat insulating member side surface 44B of the heat radiating member 44.

  Furthermore, as shown in FIGS. 8 and 9, by providing the switching IC 23 with the heat radiating plate 140 (heat radiating member for driving circuit), the heat generated from the switching IC 23 can be efficiently released to the outside of the head 100, It is possible to improve the effect of suppressing the temperature rise of the ink in the ink flow path due to this heat. Although the cross-sectional shape of the heat radiating plate 140 shown in FIG. 9 has a concave shape, in order to increase the heat radiating effect of the heat radiating plate 140, protrusions and concave portions are provided in the concave portions of the concave shape, etc. The surface area of the plate 140 is increased, and further improvement of the heat dissipation effect is expected.

  Here, the heat sink 140 is made of ceramic or metal material having high thermal conductivity. The relationship between the thermal conductivity α2 of the heat sink 140 and the thermal conductivity γ of the insulating structural member 40 satisfies the following equation [Equation 8].

[Equation 8]
α2> γ
The relationship between the thermal conductivity α2 of the heat radiating plate 140 and the thermal conductivity α1 of the heat radiating member 44 may be α2 = α1, or α2> α1 and α2 <α1.

The head 100 configured as described above has a switching IC 23 around the nozzle / pressure chamber region 110 (that is, the peripheral region of the head structure 120) obtained by projecting the two-dimensionally arranged nozzles 12 onto the opposite side surface 44A of the heat insulating member. Therefore, it is possible to easily arrange the electric wiring patterns without increasing the arrangement density. Preferably, the switching IC 23 is disposed so as to avoid the ink flow path range 130 corresponding to the region where the ink flow path is disposed, and more preferably, the switching IC 23 includes the heat radiation plate 140.

[Third Embodiment]
Next, a liquid ejection head according to a third embodiment of the invention will be described. In the third embodiment, parts that are the same as or similar to those in the first and second embodiments described above are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 10 is a cross-sectional view showing the three-dimensional structure of the head 200 according to the third embodiment. Similar to the heads 10 and 100 shown in the first and second embodiments, the head 200 shown in FIG. 10 has a laminated structure in which a plurality of cavity plates are laminated, and on the opposite side of the pressure plate 24 from the pressure chamber 14. A common liquid chamber plate 202 in which a supply port 204 for supplying ink from the common liquid chamber 16 or an ink supply system (not shown) to the common liquid chamber 16 is formed is laminated, and the common liquid chamber plate 202 is further insulated. The member 42 and the heat radiating member 44 are stacked.

  In other words, the common liquid chamber plate 202 functions as the insulating structural member 40 shown in the first and second embodiments.

  That is, in the head 200, the piezoelectric element 26 is provided on the surface (piezoelectric element disposition surface 24A) opposite to the pressure chamber 14 of the pressure plate 24 constituting the top surface of the pressure chamber 14 having the nozzle 12 and the supply throttle 18. An insulating structural member 40 having a vertical conductive member 38 electrically connected to the pad 22 on the pad 22 provided and drawn out from the individual electrode 28 of the piezoelectric element 26 to the piezoelectric element disposition surface 24A. Are arranged so as to penetrate the common liquid chamber 16.

  The end of the vertical conductive member 38 opposite to the end joined to the pad 22 is connected to the horizontal conductive member 46 formed on the heat insulating member 42 or the heat radiating member 44 or the switching IC 23 mounted on the side surface 44A opposite to the heat insulating member. Be joined.

  In the head 200 shown in FIG. 10, the vertical conductive member 38 formed so as to penetrate the common liquid chamber 16 has a structure covered with the insulating structural member 40 and is accommodated in the common liquid chamber 16. Electrical insulation with ink is ensured and protected from ink.

  In other words, the vertical conductive member 38 and the insulating structural member 40 that vertically rise like a column on the pad 22 provided by being drawn out from the individual electrode 28 for each pressure chamber 14 are the heat insulating member 42 and the heat radiating member 44. A space serving as a common liquid chamber 16 is formed by supporting an electrical wiring structure 45 on which a vertical conductive member 38 and a horizontal conductive member 46 that transmit a drive signal applied to the piezoelectric element 26 are formed from below. The vertical conductive member 38 and the insulating structural member 40 that stand up in this way may be hereinafter referred to as electric columns because of their shapes.

  FIG. 10 shows an aspect in which the width of one end (upper end) of the electric column has a substantially tapered shape that is larger than the width of the other end (lower end). However, the present invention is not limited to this, and it may be a shape having substantially the same width over the entire region between both end portions, or may be a shape in which the width of the substantially central portion is larger (smaller) than the width of both end portions.

  The common liquid chamber 16 is one large space formed over the entire region where each pressure chamber 14 is disposed, and has a surface shape corresponding to the pressure chamber disposition surface. Ink is supplied from the planar common liquid chamber 16 to each pressure chamber 14 via a supply throttle 18 provided on the pressure plate 24 corresponding to each pressure chamber 14.

In this example, an aspect in which one common liquid chamber 16 that supplies ink to all the pressure chambers 14 is provided is shown, but the common liquid chamber 16 may be divided into two or more regions.

  When the head 200 is configured as shown in FIG. 10, the arrangement of the vertical conductive members 38 can be dispersed and the horizontal conductive member 46 can be dispersed in a plurality of layers. Regardless of this, restrictions on the mounting position of the switching IC 23 and the arrangement of the electric wiring pattern on the switching IC 23 are reduced.

  In addition, it is configured to be directly connected to the common liquid chamber 16 in the vertical direction via a short ink channel (in this example, a supply throttle 18 having a channel length corresponding to the thickness of the pressure plate 24) above the pressure chamber 14. Then, the flow path resistance of the supply side flow path for supplying ink to the pressure chamber 14 can be reduced, and high-speed refilling corresponding to ink discharge at a high discharge frequency is possible. Therefore, even with an ink having a viscosity higher than that of a general ink, a predetermined ejection frequency can be secured and stable ejection can be performed.

  11A to 11F show a manufacturing process for manufacturing the head 200 by forming the common liquid chamber plate 202 (insulating structural member 40) by integral molding of resin.

  First, as shown in FIG. 11A, an insulating structural member 40 that supports the common liquid chamber 16 is integrally molded by resin molding. At this time, a through hole 220 is formed in a portion where the vertical conductive member 38 is formed. A pin may be inserted into a portion that becomes the through hole 220 at the time of resin molding, and the through hole 220 may be formed by removing the pin after molding, or the through hole 220 may be formed by laser processing or the like after molding.

  Next, as shown in FIG. 11 (b), a vertical conductive member 38 is formed in the through hole 220 by plating and conductive paste, and on the upper surface side opposite to the common liquid chamber 16 of the insulating structural member 40. Then, a patterned horizontal conductive member 46 is formed.

  When the vertical conductive member 38 and the horizontal conductive member 46 are formed on the insulating structural member 40 in this way, the vertical conductive member is previously formed on the upper surface side of the insulating structural member 40 as shown in FIG. The heat insulating member 42 and the heat radiating member 44 on which the member 38 and the horizontal conductive member 46 are formed are laminated.

  At the same time, the vertical conductive member 38 and the horizontal conductive member 46 to be electrically joined are joined by a conductive adhesive or solder.

  Thereafter, as shown in FIG. 11 (d), the mounting pattern and bumps 52 of the bare chip 50 (switching IC 23, see FIG. 11 (e)) are formed, and as shown in FIG. Mounted at the mounting position.

  In the structure thus configured, as shown in FIG. 11 (f), the piezoelectric element arrangement of the flow path structure 230 in which the nozzle 12, the pressure chamber 14, the pressure plate 24, and the piezoelectric element 26 are formed. The pads 22 formed on the surface 24A and the vertical conductive members 38 corresponding to the pads 22 are joined, and a predetermined insulation process is performed, whereby the head 200 is completed.

  In this example, the vertical conductive member 38 is provided for each piezoelectric element 26. However, a common vertical conductive member 38 may be provided for a plurality of piezoelectric elements 26. Further, the vertical conductive member 38 may transmit not only a drive signal for the piezoelectric element 26 but also a signal obtained from sensors provided in the pressure chamber 14.

[Fourth Embodiment]
Next, a liquid ejection head according to a fourth embodiment of the invention will be described.

  FIG. 12 shows a head 300 according to the fourth embodiment. The head 300 includes a plurality of head modules having the same configuration as the heads 10, 100, and 200 shown in the first to third embodiments, and corresponds to the entire printable width (dischargeable width) of the medium. It is configured to be a full-line head with a length.

  The head 300 shown in FIG. 12 has the same configuration, and has a structure in which five head modules 302 (302-1 to 302-5) having a length shorter than the media dischargeable width are arranged in a staggered manner. Yes.

  Each head module 302 is equipped with a switching IC 23 corresponding to the number of piezoelectric elements 26 (nozzles 12) included in each head module 302. In this example, a plurality of switching ICs 23 that can drive 512 (or 256) piezoelectric elements 26 are provided and correspond to the piezoelectric elements 26 included in each head module 302.

  In other words, the size (the number of nozzles) of the head module 302 is determined so that the switching IC 23 that can be mounted on one head module 302 includes the corresponding number of nozzles 12.

  As shown in FIG. 12, by configuring the full-line head 300 from a plurality of head modules 302, the area where the switching IC 23 can be mounted can be expanded, and maintenance operations such as purging and suctioning can be performed. It can be executed for each head module. In addition, since the head module can be replaced in the event of a failure, maintenance is expected to be improved.

  Note that the switching IC 23 may be mounted on the heat insulating member opposite side surface 44 </ b> A (upper surface side of the head module 302) of the heat radiating member 44, or may be mounted on the heat insulating member side surface 44 </ b> B (back surface side).

[Overall configuration of inkjet recording apparatus]
Next, an ink jet recording apparatus to which the liquid discharge head 10 (100, 200, 300) according to the first to fourth embodiments described above is applied will be described.

  FIG. 13 is an overall configuration diagram of an ink jet recording apparatus equipped with a liquid discharge head (ink jet head) according to the present invention. As shown in the drawing, the ink jet recording apparatus 400 includes a plurality of print heads 412K provided corresponding to black (K), cyan (C), magenta (M), and yellow (Y) inks. A printing unit 402 having 412C, 412M, and 412Y, an ink storage / loading unit 404 for storing ink to be supplied to each printing head (recording head) 412K, 412C, 412M, and 412Y, and a recording paper 416 as a recording medium Is disposed opposite to the ink ejection surface of the printing unit 412 and maintains the flatness of the recording paper 416 while maintaining the flatness of the recording paper 416. A suction belt conveyance unit 422 that conveys 416, a print detection unit 424 that reads a printing result by the printing unit 412, and a printed recording paper 416 (print ) It is provided with a paper discharge unit 426 for discharging, to the outside.

  The ink storage / loading unit 414 includes ink tanks that store inks of colors corresponding to the heads 412K, 412C, 412M, and 412Y. Communicated with. In addition, the ink storage / loading unit 414 includes notifying means (display means, warning sound generating means) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. ing.

  In FIG. 13, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 418, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 428 for cutting is provided as shown in FIG. 13, and the roll paper is cut into a desired size by the cutter 428. The cutter 428 includes a fixed blade 428A having a length equal to or greater than the conveyance path width of the recording paper 416 and a round blade 428B that moves along the fixed blade 428A. The fixed blade 428A is provided on the back side of the print. The round blade 428B is disposed on the printing surface side across the conveyance path. Note that the cutter 428 is not necessary when cut paper is used.

  In the case of a configuration in which a plurality of types of recording paper can be used, an information recording body such as a barcode or a wireless tag that records the paper type information is attached to the cassette, and the information on the information recording body is read by a predetermined reading device. Thus, it is preferable to automatically determine the type of recording medium (media type) to be used and perform ink ejection control so as to realize appropriate ink ejection according to the media type.

  The recording paper 416 delivered from the paper supply unit 418 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 416 by the heating drum 430 in the direction opposite to the curl direction of the magazine in the decurling unit 420. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  The decurled recording paper 416 is sent to the suction belt conveyance unit 422. The suction belt conveyance unit 422 has a structure in which an endless belt 433 is wound between rollers 431 and 432, and at least a portion facing the nozzle surface of the printing unit 412 forms a horizontal plane (flat surface). Has been.

  The belt 433 has a width that is greater than the width of the recording paper 416, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 13, an adsorption chamber 434 is provided at a position facing the nozzle surface of the printing unit 412 inside the belt 433 spanned between the rollers 431 and 432, and the adsorption chamber 434 is connected to the fan 435. The recording paper 416 is sucked and held on the belt 433 by suctioning at a negative pressure.

  When the power of a motor (not shown in FIG. 13, not shown in FIG. 15 is indicated by reference numeral 488) is transmitted to at least one of the rollers 431 and 432 around which the belt 433 is wound, the belt 433 is rotated clockwise in FIG. The recording paper 416 held on the belt 433 is conveyed from left to right in FIG.

  Since ink adheres to the belt 433 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 433 (an appropriate position other than the print region). Although details of the configuration of the belt cleaning unit 436 are not illustrated, for example, there are a method of niping a brush roll, a water absorption roll, etc., an air blow method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  It is possible to use a roller / nip conveyance mechanism instead of the suction belt conveyance unit 422. However, if the roller / nip conveyance is performed in the printing area, the roller is brought into contact with the printing surface of the sheet immediately after printing, so that the image is likely to spread. There is a problem. Therefore, as in this example, suction belt conveyance that does not bring the image surface into contact with each other in the print region is preferable.

  A heating fan 440 is provided on the upstream side of the printing unit 412 on the paper conveyance path formed by the suction belt conveyance unit 422. The heating fan 440 heats the recording paper 416 by blowing heated air onto the recording paper 416 before printing. Heating the recording paper 416 immediately before printing makes it easier for the ink to dry after landing.

  Each print head 412K, 412C, 412M, 412Y of the print unit 412 has a length corresponding to the maximum paper width (required print width) of the recording paper 416 targeted by the inkjet recording apparatus 400, and the nozzle surface has This is a full-line print head in which a plurality of nozzles for ejecting ink are arranged over a length exceeding the length of at least one side of the recording medium of the maximum size (full width of the drawable range) (see FIG. 14).

  The print heads 412K, 412C, 412M, and 412Y are arranged in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side along the feeding direction (sub-scanning direction) of the recording paper 416. The print heads 412K, 412C, 412M, and 412Y are fixedly installed so as to extend along a direction substantially orthogonal to the feeding direction of the recording paper 416.

  A color image can be formed on the recording paper 416 by discharging different color inks from the heads 412K, 412C, 412M, and 412Y while conveying the recording paper 416 by the suction belt conveyance unit 422.

  As described above, according to the configuration in which the full-line type print heads 412K, 412C, 412M, and 412Y having nozzle rows covering the entire width of the paper are provided for each color, the recording paper 416 and the printing unit 412 are relatively arranged in the recording paper feeding direction. Thus, the image can be recorded on the entire surface of the recording paper 416 by performing the movement operation only once (that is, by one sub-scan). Thereby, printing can be performed at a higher speed than the shuttle type head in which the print head reciprocates in the direction orthogonal to the paper conveyance direction, and productivity can be improved.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink may be added as necessary. Good. For example, it is possible to add a print head that discharges light ink such as light cyan and light magenta. Also, the arrangement order of the color heads is not particularly limited.

  A post-drying unit 442 is provided following the printing unit 412. The post-drying unit 442 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by pressurizing the paper holes with pressure. There is an effect to.

  A heating / pressurizing unit 444 is provided following the post-drying unit 442. The heating / pressurizing unit 444 is a means for controlling the glossiness of the image surface, and pressurizes the image surface with a pressure roller 445 having a concavo-convex shape on a predetermined surface, thereby forming the concavo-convex shape on the image surface. Transcript.

  The printed matter generated in this manner is outputted from the paper output unit 426. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 400 is provided with sorting means (not shown) for switching the paper discharge path in order to select the print product of the main image and the print product of the test print and send them to the paper output units 426A and 426B. ing. In the configuration using roll paper, when the main image and the test print are simultaneously formed on a large paper in parallel, the test print portion is separated by a cutter (not shown) (second cutter). The second cutter is provided immediately before the paper discharge unit 426, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the 2nd cutter is the same as that of the 1st cutter mentioned above, and comprises a fixed blade and a round blade.

  Although not shown in FIG. 13, the paper output unit 426A for the target prints is provided with a sorter for collecting prints according to print orders.

[Explanation of control system]
FIG. 15 is a principal block diagram showing the system configuration of the inkjet recording apparatus 400. The inkjet recording apparatus 400 includes a communication interface 470, a system controller 472, an image memory 474, a motor driver 476, a heater driver 478, a print control unit 480, an image buffer memory 482, a head driver 484, and the like.

  The communication interface 470 is an interface unit that receives image data sent from the host computer 486. As the communication interface 470, a serial interface such as USB, IEEE 1394, Ethernet, or wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. Image data sent from the host computer 486 is taken into the inkjet recording apparatus 400 via the communication interface 470 and temporarily stored in the image memory 474.

  The image memory 474 is a storage unit that temporarily stores an image input via the communication interface 470, and data is read and written through the system controller 472. The image memory 474 is not limited to a memory composed of semiconductor elements, and a magnetic medium such as a hard disk may be used.

  The system controller 472 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 400 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. . That is, the system controller 472 controls each part such as the communication interface 470, the image memory 474, the motor driver 476, the heater driver 478, etc., performs communication control with the host computer 486, read / write control of the image memory 474, etc. A control signal for controlling the motor 488 and the heater 489 of the transport system is generated.

  The motor driver 476 is a driver that drives the motor 488 in accordance with an instruction from the system controller 472. The heater driver 478 is a driver that drives the heater 489 such as the post-drying unit 442 in accordance with an instruction from the system controller 472.

  The print control unit 480 has a signal processing function for performing various processing and correction processes for generating a print control signal from image data in the image memory 474 according to the control of the system controller 472, and the generated print A control unit supplies data to the head driver 484. Necessary signal processing is performed in the print control unit 480, and the ejection amount and ejection timing of the ink droplets of the print heads 412K, 412C, 412M, and 412Y are controlled via the head driver 484.

  The print control unit 480 includes an image buffer memory 482, and image data, parameters, and other data are temporarily stored in the image buffer memory 482 when image data is processed in the print control unit 480. In FIG. 15, the image buffer memory 482 is shown in a mode accompanying the print control unit 480, but it can also be used as the image memory 474. Also possible is an aspect in which the print control unit 480 and the system controller 472 are integrated to form a single processor.

  The head driver 484 generates a drive signal based on the print data given from the print control unit 480, and drives the piezoelectric elements of the heads 412K, 412C, 412M, 412Y of each color by this drive signal. The head driver 484 may include a feedback control system for keeping the head driving condition constant.

  Data of an image to be printed (image data in which the image size and resolution are converted in accordance with the size of the recording paper 416) is input from the outside via the communication interface 470 and stored in the image memory 474. At this stage, RGB image data is stored in the image memory 474.

  The image data stored in the image memory 474 is sent to the print control unit 480 via the system controller 472, and is converted into dot data for each ink color by the print control unit 480. That is, the print control unit 480 performs processing for converting the input RGB image data into KCMY four-color dot data. The dot data generated by the print control unit 480 is stored in the image buffer memory 482.

  Various control programs are stored in the program storage unit 490, and the control programs are read and executed in accordance with instructions from the system controller 472. The program storage unit 490 may use a semiconductor memory such as a ROM or an EEPROM, or may use a magnetic disk or the like. An external interface may be provided and a memory card or PC card may be used. Of course, you may provide several recording media among these recording media.

  The program storage unit 490 may also be used as recording means (memory) (not shown) such as operation parameters (system parameters).

  As described with reference to FIG. 13, the print detection unit 424 is a block including a line sensor. The print detection unit 424 reads an image printed on the recording paper 416, performs necessary signal processing, etc. And the detection result is provided to the print control unit 480.

  The print control unit 480 performs various corrections for the print heads 412K, 412C, 412M, and 412Y based on information obtained from the print detection unit 424 as necessary.

  In the example shown in FIG. 13, the print detection unit 424 is provided on the print surface side, and the print surface is illuminated by a light source (not shown) such as a cold cathode tube arranged near the line sensor. Although the configuration is such that the reflected light is read by the line sensor, other configurations may be used in the implementation of the present invention.

  In this example, the ink jet recording apparatus 400 that forms an image on the recording paper 416 by ejecting ink from the nozzles provided in the print head is shown, but the scope of the present invention is not limited to this, and the processing liquid, The present invention can be widely applied to a liquid discharge apparatus such as a dispenser that discharges a liquid such as a chemical solution or water onto a discharge medium.

FIG. 2 is a perspective plan view showing a structural example of the liquid ejection head according to the first embodiment of the present invention. 1 is a cross-sectional view taken along line 2-2 in FIG. FIG. 2 is a diagram illustrating a detailed structure of the liquid discharge head shown in FIG. Plane perspective view showing a structural example of a liquid ejection head according to a second embodiment of the present invention 4 is a sectional view taken along line 5-5 in FIG. The perspective view which shows the structural example of the liquid discharge head which concerns on 3rd Embodiment of this invention. The figure explaining the ink flow path range shown in FIG. The perspective view which shows the one aspect | mode of the liquid discharge head shown in FIG. 8 is a cross-sectional view taken along line 5 (9) -5 (9) in FIG. Sectional drawing which shows the structural example of the liquid discharge head which concerns on 3rd Embodiment of this invention. The figure explaining the manufacturing process of the liquid discharge head shown in FIG. The top view which shows the structure of the head which concerns on 4th Embodiment of this invention. 1 is an overall configuration diagram of an ink jet recording apparatus equipped with a liquid discharge head according to the present invention. FIG. 13 is a plan view of the main part around the printing unit of the ink jet recording apparatus shown in FIG. FIG. 13 is a principal block diagram showing the system configuration of the ink jet recording apparatus shown in FIG.

Explanation of symbols

10, 100, 200, 300, 412K, 412C, 412M, 412Y ... Liquid discharge head, 12 ... Nozzle, 14 ... Pressure chamber, 16 ... Common liquid chamber, 18 ... Supply throttle, 23 ... Switching IC, 26 ... Piezoelectric element, 28 ... Individual electrode, 36 ... Pad, 38 ... Vertical conductive member, 40 ... Insulating structural member, 42 ... Thermal insulation member, 44 ... Heat radiation member, 46 ... Horizontal conductive member, 50 ... Bare chip, 52 ... Projection electrode, 140 ... Heat radiation Plate, 302 ... head module

Claims (11)

A plurality of two-dimensionally arranged discharge holes for discharging liquid onto the discharge medium;
A plurality of pressure chambers provided corresponding to the plurality of discharge holes and containing liquid discharged from the discharge holes;
A common liquid chamber for supplying liquid to the plurality of pressure chambers;
A piezoelectric element provided on a wall facing the wall in which the discharge hole is formed among the walls constituting the pressure chamber, and having an individual electrode to which a drive signal is input;
An extraction electrode that is taken out from the individual electrode of the piezoelectric element and is electrically joined to the individual electrode;
A structural member joined to a surface of the wall constituting the pressure chamber opposite to the liquid discharge direction;
A drive circuit that is mounted on the surface of the structural member in contact with the atmosphere and that generates a drive signal to be applied to the piezoelectric element;
With
The structural member has a laminated structure in which two or more members are laminated, and at least the outermost layer in contact with the atmosphere is composed of a heat dissipation member and has at least one heat insulating member,
The member forming the structural member is at least the vertical conductive member among a vertical conductive member formed in a direction substantially perpendicular to a surface to which the piezoelectric element is attached and a horizontal conductive member formed in a direction substantially orthogonal to the vertical conductive member. A liquid discharge head comprising a conductive member including a conductive member, one end of which is joined to the extraction electrode and the other end is joined to the drive circuit.   The liquid discharging head according to claim 1, wherein the structural member includes an insulating structural member bonded to a surface of the wall constituting the pressure chamber opposite to the liquid discharging direction. The drive circuit has a structure integrated in one or more ICs,
3. The liquid discharge head according to claim 1, wherein the IC is flip-chip mounted on a surface of the heat radiating member on which the driving circuit is mounted. The relationship between the heat conductivity α1 of the heat radiating member and the heat conductivity β of the heat insulating member is expressed by the following equation: α1> β
The liquid discharge head according to claim 1, wherein:   5. The liquid ejection head according to claim 1, wherein the heat insulating member includes a thermosetting epoxy resin or a member in which inorganic fine particles are contained in a thermosetting epoxy resin. 6.   The liquid ejection head according to claim 1, wherein the drive circuit includes a heat radiating member for a drive circuit. The relationship between the thermal conductivity α2 of the heat radiating member for the drive circuit and the thermal conductivity β of the heat insulating member is expressed by the following formula: α2> β
The liquid discharge head according to claim 6, wherein: The common liquid chamber and the piezoelectric element are provided on the side opposite to the liquid discharge direction of the pressure chamber,
The conductive member is provided so as to rise from the surface on which the piezoelectric element is disposed and penetrate the common liquid chamber, one end is joined to the extraction electrode, and the other end is joined to the drive circuit. The liquid discharge head according to claim 1, wherein the liquid discharge head is a liquid discharge head. 9. The drive circuit according to claim 1, wherein the drive circuit is disposed in a region corresponding to a non-arrangement region of the pressure chamber or the common liquid chamber among regions in contact with the heat radiating member. Or one
The liquid discharge head according to item.   10. The liquid discharge head according to claim 1, wherein the discharge holes have a structure in which the discharge holes are arranged over a length corresponding to a full width of the liquid dischargeable width of the discharge medium.   Having a structure in which a plurality of liquid discharge head modules each having a discharge hole array in which the discharge holes are arranged over a length less than the full width of the liquid dischargeable of the discharge medium are arranged in the width direction of the discharge medium. The liquid discharge head according to claim 10.

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